Industrial furnaces such as, for example, aluminum melting furnaces must be heated and kept warm with burners. It is thereby known to utilize regenerators through which hot exhaust gas and cold combustion air flow in alternation. The regenerators being in the position, as heat store, to preheat cold combustion air to high temperature, energy being thereby saved. In the regenerator, the hot exhaust gas cools, for example, from 1200.degree. C. to, for example, 400.degree. C., whereas the cold combustion air can be preheated to, for example, 1000.degree. C. in the regenerator in a following period.
Embodiments previously disclosed for heating industrial furnaces with employment of regenerators and burners proceed on the basis of a paired or, respectively, symmetrical arrangement of the regenerators/burners in a single unit. For example, the storing of the exhaust heat in one regenerator of one pair ensues in the exhaust gas mode (heating periods) and the unstoring of the heat of other regenerator ensues in the other regenerator/burner pair by alternately switching to the burner mode (cooling period) (for example, GB-A-2 224 563). As a result of the strictly paired, symmetrical allocation and operation of the two regenerators, however, individually different thermic conditions of the regenerators as well as time and space demands in view of the heat requirements for the operation of the smelting furnace cannot be taken into consideration, and a fast replacement of the regenerator/burner modules cannot be undertaken in case of maintenance and repair.